How does Gmail’s “importance marker” algorithm function?

Gmail's importance marker algorithm evaluates which emails deserve priority attention by analyzing multiple signals. It considers your relationship with the sender: frequent correspondents and direct replies get higher importance. It examines whether you typically read and respond to similar messages.

Keywords in subject lines and content influence importance scoring, as do patterns in your reading behavior. If you always open emails from certain senders immediately, Gmail learns to mark their future messages as important.

For bulk senders, importance markers rarely apply because the algorithm focuses on personal correspondence patterns. However, understanding this system explains why transactional emails sometimes receive different treatment than marketing emails, even from the same sender domain. Gmail tries to surface messages that match individual user priorities.